1. Field of the Invention
The present invention relates to a novel chewing gum composition and in particular to a sucralose sweetened chewing gum composition having a moisture content below about 2% by weight of the final composition wherein said composition contains a chewing gum base, at least one sugar alcohol and about 0.5% to about 20% hygroscopic liquid by weight of the final chewing gum composition. The present invention also relates to a process for preparing the chewing gum composition of the present invention.
2. Description of Related Art
Chewing gums and bubble gums have been prepared in the past with the purpose in mind of extending shelf life, increasing initial flavor and sweetener intensity and prolonging long lasting sweetness and flavor without bitterness being developed. With regard to shelf stability, gums prepared and stored, even at room temperature, for extended periods of time tend to lose their moisture and elasticity, with the result that they become brittle, and initially crumble when they are placed in the mouth. This problem is particularly noticeable in the instance of sugarless gums, and particularly those gums that are stored in a dry atmosphere, for example atmospheres having less than about 50 to 60% relative humidity.
Sugarless gums conventionally contain on the order of at least about 5% by weight of water; and it is therefore theorized that brittleness or the phenomenon of staling results from the loss of that water, due to evaporation or otherwise over time. Specifically, sugarless gums contain large amounts of sorbitol which serves conventionally as a sweetener as well as a bulking aid. Sorbitol is known for its tendency to recrystallize in the presence of even small amounts of water and its tendency to crystallize when the water in which it is dissolved is removed. It is therefore theorized that as the water containing the sorbitol in the gum composition is lost by evaporation or otherwise, the sorbitol crystallizes and thus promotes the embrittlement of the gum composition that contributes to the staling phenomenon.
In addition the prior art has disclosed chewing gum compositions which have low percentages of moisture in the final product. For the most part, the prior art has concentrated on driving off the water once the chewing gum formulation has been made. Thus the prior art compositions ordinarily contain water and/or moisture containing ingredients, e.g., sorbitol solutions, corn syrups solutions and so forth, and would therefore require heating or purification of the composition to drive off water and obtain a certain moisture content.
In this regard, U.S. Pat. No. 4,035,572 discloses a gum base formulation with less than about 0.5% moisture. This low percentage of moisture is due to the purification process which removes water and solvent from the gum base. U.S. Pat. No. 4,382,963 involves a low calorie chewing gum which uses polydextrose as the sole soluble bulking agent. The moisture content in the final product is about 1 to 5% and thus is obtained by omitting the aqueous component, namely sorbitol, syrups or corn syrup solids, which are normally used in chewing gum products.
U.S. Pat. No. 3,262,784 concerns a chewing gum composition which has less than 1% moisture in the final product, due to heating between about 170.degree. and 250.degree. F. to drive off the water.
U.S. Pat. No. 4,150,161 concerns a two component confectionery formulation having a carbonated candy component and a pliable bubble gum component, with each component having a controlled water activity between 0.1 and 0.3 and which is capable of surviving long periods of storage when packaged in a moisture-resistant material.
U.S. Pat. No. 4,514,422 to YANG et al. discloses a substantially anhydrous chewing gum composition which is useful in the chewing gum formulations of this invention. These formulations contain a gum base, sugar alcohol and glycerin in amounts greater than 10% to about 18%, with disclosed amounts above 8% being usable. The disclosure of this reference is incorporated herein by reference.
The prior art chewing gum formulations have been used in combination with both natural and artificial sweeteners. Intense artificial sweeteners that have been disclosed for use in chewing gum formulations include the water-soluble artificial sweeteners, such as soluble saccharin salts such as sodium or calcium saccharin, cyclamate salts, acesulfame-K and the like and the free acid form of saccharin. In addition, dipeptide based sweeteners such as L-aspartyl-L-phenylalanine methyl ester and materials described in U.S. Pat. No. 3,492,131 and the like have also been described.
In addition to these artificial sweeteners, another artificial sweetener, namely sucralose, has been recently described in U.S. Pat. 4,380,476, along with its use in ingestable products as described in U.S. Pat. Nos. 4,549,013 and 4,435,440. Sucralose is reported to be 600 to 650 times as sweet as sucrose and has the chemical name 4-1'-6'-trichlorogalactosucrose, and has been abbreviated a chloro-derivative of sucrose. This particular sweetener is a high intensity artificial sweetener, since it is many times more sweet than sucrose itself, similar to saccharin which is about 300 times as sweet as sucrose, aspartame which is about 200 times as sweet as sucrose and acesulfame-K which is about 200 times as sweet as sucrose.
Several limitations have existed in chewing gum formulations which relate to the rate at which the sweetener is released from the chewing gum composition when it is being chewed. Such release normally occurs in both sugar and non-sugar sweetened chewing gum formulations within times of from 5 to 7 minutes upon commencement of chewing. In view of this rate of release of sweetener from the chewing gum within the first several minutes of chewing, chewing gum manufacturers have attempted to not only increase the intensity of the sweetener which is delivered initially upon chewing of the gum, but also to delay the sweetness release over a longer period of time and in particular for times of up to about 25 to 30 minutes.
The ability to achieve high intensity up-front sweetness has been achieved by using artificial intense sweeteners, such as saccharin salts, acesulfame-K and free aspartame in chewing gum formulations in amounts of about 0.05 to about 0.2% by weight of the formulation. One problem relating to the use of saccharin salts and acesulfame-K is the bitterness/off-note taste associated with such products, whereas aspartame degrades in its free form in the presence of moisture in conventional chewing gums. Even at low levels of about 2 or more per cent moisture, the aspartame will be degraded upon storage thus rendering it unavailable when the chewing gum is to be utilized.
With regard to delayed release or longer lasting release chewing gum formulations, various techniques have been employed in the art, such as encapsulation of the sweetener components and use of sweetener-enhancing compounds, such as thaumatin and monellin. PCT application W088/08672 also discloses a chewing gum composition having a controlled long lasting sweetness release comprising a gum base and an effective amount of the sweetener sucralose. The chewing gum contains sucralose in an amount such that within the initial two minutes of chewing the sucralose releases from the gum at a rate less than about 8 sucrose equivalents per minute; and at about 10 minutes of chewing, the sucralose releases from said gum at a rate of about 3 sucrose equivalents per minute. The chewing gum, in addition, may also contain a fast release sweetener, or an additional amount of sucrose treated to act as a fast release sweetener. More particularly the technology described in this publication relates to an initial slow release of sucralose from the chewing gum formulation with a continued sustained or delayed longer lasting sweetness release throughout chewing. The reference, however, is silent as to how delayed release is achieved.
It remains desirable, however, to prepare a chewing gum formulation which does not possess the instability problems associated with the use of aspartame and bitterness/off-note taste associated with saccharin salts and acesulfame-K, yet one which is capable of rapidly releasing the sweetener upon initial chewing of the formulation and is capable of extended sweetener release. This initial onset of sweetness should be performed in the absence of a concurrent bitterness associated with high intensity sweeteners. Such formulations may also employ sweetening components which are able to achieve a longer lasting sweetness in combination with this initial high intensity sweetness.